Dos cargas puntuales están fijas en el eje x: q1 = –3.0 µC esta en el origen, O, con x1 = 0.0 cm, y q2 =6.0 µC está situada en el punto A, con x2 = 8.0 cm. Donde debería colocarse una tercera carga, q3, sobre el eje x, de modo que
la fuerza electrostática total que actúa sobre esta sea cero? (0.25)
a) 27 cm
b) 0 cm
c) 8.0 cm
d) –27 cm

Which of the following situations is impossible? a) an object has velocity directed east and acceleration directed east. b) an object has zero velocity but non-zero acceleration. c) an object has constant non-zero velocity and changing acceleration. d) an object has velocity directed east and acceleration directed west. e) an object has constant non-zero acceleration and changing velocity.